Chen Xiao, Meng Xiaoyan, Zhu Di, Zou Xianlun, Shen Yaqi, Li Zhen, Peng Jian, Hu Daoyu
Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
Quant Imaging Med Surg. 2021 May;11(5):1828-1835. doi: 10.21037/qims-20-633.
This study sought to explore the functional relationship between displayed vascular length and blood suppression inversion time (BSP TI) and flow velocity in a phantom, and to provide a theoretical basis for quantitatively assessing vascular hemodynamic responses using unenhanced magnetic resonance angiography (MRA) and spatial labeling with multiple inversion pulses sequence (SLEEK).
A polyethylene catheter was laid in a long rectangular container filled with pork fat. The entrance of the catheter into the container was connected to a high-pressure syringe filled with normal saline. The high-pressure injector flow rates were set at 0.0, 0.2, 0.4, 0.8, 1.2, 1.6, 2.0, and 2.4 mL/s. SLEEK was performed 19 times for each flow rate with parameter BSP TI values of 50, 75, 100, 150, 200, 300, 400, 500, 600, 700, 800, 900, 1,000, 1,100, 1,200, 1,300, 1,400, 1,600, and 1,800 ms. Maximum intensity projection was employed to reconstruct all SLEEK original images to determine the measurements of the displayed vascular lengths. A regression analysis was undertaken to assess the relationship between the displayed vascular lengths and BSP TI values for each flow rate, and to assess the relationship between the displayed vascular lengths and flow rates at each BSP TI.
The displayed vascular length had a linear relationship with BSP TI for each flow rate (P<0.05) (R2=0.754, 0.941, 0.988, 0.988, 0.977, 0.966, and 0.982 for flow rates of 0.0, 0.2, 0.4, 0.8, 1.2, 1.6, and 2.0 mL/s, respectively). The displayed vascular length also had a linear relationship with flow rate for each BSP TI value (P<0.05) (R2 =0.914, 0.912, 0.834, 0.989, 0.980, 0.996, 0.992, 0.960, 0.975, 0.979, 0.982, 0.981, 0.976, and 0.993 for BSP TI 50, 75, 100, 150, 200, 300, 400, 500, 600, 700, 800, 900, 1,000, and 1,100 ms, respectively). No significant linear relationship was found between displayed vascular length and flow rate when the BSP TI value was 1,200 ms (P>0.05).
Vascular displayed length has a linear relationship to BSP TI for flow ranges from 0.0 to 2.0 mL/s. Vascular displayed length has a linear relationship to flow rate for BSP TI values of 50 to 1,100 ms. Flow rate can be assessed in relation to vascular displayed length.
本研究旨在探讨在模型中显示的血管长度与血液抑制反转时间（BSP TI）及流速之间的功能关系，为使用非增强磁共振血管造影（MRA）和多反转脉冲序列空间标记（SLEEK）定量评估血管血流动力学反应提供理论依据。
将一根聚乙烯导管放置在一个装满猪脂肪的长方形容器中。导管进入容器的入口连接到一个装有生理盐水的高压注射器上。高压注射器的流速设置为0.0、0.2、0.4、0.8、1.2、1.6、2.0和2.4 mL/s。对于每个流速，以50、75、100、150、200、300、400、500、600、700、800、900、1000、1100、1200、1300、1400、1600和1800 ms的参数BSP TI值进行19次SLEEK检查。采用最大强度投影重建所有SLEEK原始图像，以确定显示的血管长度测量值。进行回归分析，以评估每个流速下显示的血管长度与BSP TI值之间的关系，以及每个BSP TI下显示的血管长度与流速之间的关系。
对于每个流速，显示的血管长度与BSP TI呈线性关系（P<0.05）（流速为0.0、0.2、0.4、0.8、1.2、1.6和2.0 mL/s时，R2分别为0.754、0.941、0.988、0.988、0.977、0.966和0.982）。对于每个BSP TI值，显示的血管长度与流速也呈线性关系（P<0.05）（BSP TI为50、75、100、150、200、300、400、500、600、700、800、900、1000和1100 ms时，R2分别为0.914、0.912、0.834、0.989、0.980、0.996、0.992、0.960、0.975、0.979、0.982、0.981、0.976和0.993）。当BSP TI值为1200 ms时，显示的血管长度与流速之间未发现显著的线性关系（P>0.05）。
在0.0至2.0 mL/s的流速范围内，血管显示长度与BSP TI呈线性关系。在50至1100 ms的BSP TI值范围内，血管显示长度与流速呈线性关系。流速可根据血管显示长度进行评估。
